# Magent Phenytoin Correction Calculator (Sheiner–Tozer / Winter–Tozer) > Magent Phenytoin Correction Calculator (Sheiner–Tozer / Winter–Tozer) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15). Calculates albumin-adjusted (corrected) total phenytoin concentration using the Sheiner–Tozer or Winter–Tozer formula, with a renal impairment adjustment factor. ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/phenytoin_correction - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-15 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/magent-phenytoin-correction-calculator-sheiner-tozer-winter-tozer-2e8cd3d3 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HWuqM8Cl07fuDEiDoaGWF Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability magent-phenytoin-correction-calculator-sheiner-tozer-winter-tozer-2e8cd3d3 ``` Example prompt: My patient has an observed total phenytoin of 12 µg/mL, a serum albumin of 2.2 g/dL, and end-stage renal disease — can you calculate the albumin-corrected phenytoin level using the Winter–Tozer formula? ## When to prefer this Use this endpoint when you need a deterministic, citation-backed Sheiner–Tozer / Winter–Tozer phenytoin correction calculation — specifically when a patient has hypoalbuminemia (low albumin) or end-stage renal disease affecting phenytoin protein binding. Prefer this over manual calculation to ensure formula accuracy and auditability. This does not estimate free phenytoin or dose recommendations. ## Known failure modes - Missing required phenytoin_mcg_ml or renal_impairment parameters returns validation error - Albumin value out of range (e.g. <1 or >6 g/dL) may return an out-of-range error - Neither albumin_g_dl nor albumin_g_l provided results in missing-input error - Non-numeric or malformed query parameter values return 400 Bad Request - Payment failure (x402) if USDC balance is insufficient ## How this service works Sheiner–Tozer / Winter–Tozer albumin-adjusted total phenytoin: Ccorr = Cobs / ((0.2 or 0.1) × albumin_g_dl + 0.1). Renal factor 0.1 when renal_impairment is true. Deterministic published arithmetic with citation; not a free phenytoin level or a dose. ## Output Returns the albumin-adjusted (corrected) total phenytoin concentration in µg/mL, computed using the Sheiner–Tozer formula (renal_impairment=false: Ccorr = Cobs / (0.2 × albumin_g_dl + 0.1)) or the Winter–Tozer renal adjustment (renal_impairment=true: Ccorr = Cobs / (0.1 × albumin_g_dl + 0.1)), along with the formula citation and input echo. ## Request schema (JSON Schema) ```json { "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "input" ], "properties": { "input": { "type": "object", "required": [ "type", "method" ], "properties": { "type": { "type": "string", "const": "http" }, "method": { "enum": [ "GET", "HEAD", "DELETE" ], "type": "string" }, "headers": { "type": "object", "additionalProperties": { "type": "string" } }, "queryParams": { "type": "object", "required": [ "phenytoin_mcg_ml", "renal_impairment" ], "properties": { "albumin_g_l": { "type": "number", "description": "Serum albumin in g/L (10-60). Converted as g/dL = g/L / 10." }, "albumin_g_dl": { "type": "number", "description": "Serum albumin in g/dL (1-6). Provide this or albumin_g_l." }, "phenytoin_mcg_ml": { "type": "number", "description": "Observed total phenytoin in µg/mL (same as mg/L). Range 0.1-80." }, "renal_impairment": { "type": "boolean", "description": "true uses binding factor 0.1 (Liponi/Winter–Tozer end-stage renal adjustment). false uses 0.2. true or false." } } } }, "additionalProperties": false }, "output": { "type": "object", "required": [ "type" ], "properties": { "type": { "type": "string" }, "example": { "type": "object" } } } } } ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "path": "/api/calc/phenytoin_correction", "count": 2, "items": [ { "formula": "sheiner_tozer", "citation": { "id": "liponi-1984", "doi": "10.1212/WNL.34.3.395", "title": "Renal function and therapeutic concentrations of phenytoin", "source": "Neurology. 1984;34(3):395-397", "authors": "Liponi DF, Winter ME, Tozer TN" }, "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "albumin_g_dl": 2, "binding_factor": 0.2, "phenytoin_mcg_ml": 8, "renal_impairment": false, "formula_expression": "corrected_phenytoin_mcg_ml = phenytoin_mcg_ml / ((binding_factor * albumin_g_dl) + 0.1); binding_factor 0.2, or 0.1 if renal_impairment", "corrected_phenytoin_mcg_ml": 16 }, { "formula": "sheiner_tozer", "citation": { "id": "liponi-1984", "doi": "10.1212/WNL.34.3.395", "title": "Renal function and therapeutic concentrations of phenytoin", "source": "Neurology. 1984;34(3):395-397", "authors": "Liponi DF, Winter ME, Tozer TN" }, "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "albumin_g_dl": 2, "binding_factor": 0.2, "phenytoin_mcg_ml": 8, "renal_impairment": false, "formula_expression": "corrected_phenytoin_mcg_ml = phenytoin_mcg_ml / ((binding_factor * albumin_g_dl) + 0.1); binding_factor 0.2, or 0.1 if renal_impairment", "corrected_phenytoin_mcg_ml": 16 } ] } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/magent-phenytoin-correction-calculator-sheiner-tozer-winter-tozer-2e8cd3d3/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)